combining MPEG/AVI-parts from newsgroups

[twoages2]

In newsgroups I often see a list of individual MPEG's files that belong together (exemple: MPEG1/3 309KB, MPEG2/3 309KB, MPEG3/3 309kb etc.)
How can I join these parts to one movie. Mostly the first MPEG (1/xx) from the sequence runs normal(there is a normal MPEG-attachment to save and run). The following parts (2/xx and further) are giving a bunch of ascii-code in the news message itself and there is no attachment to save. I assume the ascii-code must be converted to a proper MPEG-layout. I don't know how to do that. Anybody can help???

[buzzinhornets]

What extension do they end in? (for example are they files like movie.mpg.001 , movie.mpg.002 , movie.mpg.003 , etc.)
Or do they in something else?

[twoages2]

there is no extension. Did you never encounter that problem/fact?:
The first news file (calls for example "MPEGfilepart 1of12" and is first of the sequence) has the first MPEG-part as an attachment, the next news files (MPEGfilepart 2of12" etc) showing no attachments but showing a big ascii-like representation withinh the news message itself (as text).